Abstract: The process for making the high temperature-resistant ceramic material from the MgO—Al2O3 system includes burning a mixture containing a predetermined amount of magnesium oxide (MgO) of a predetermined grain size distribution in an amount range of from 30 to 99 parts by weight and a predetermined amount of magnesium aluminate (MgAl2O4) of another different predetermined grain size distribution in a range of from 1 to 70 parts by weight to obtain a ceramic product having a thermal expansion coefficient and selecting the amounts of magnesium oxide and magnesium aluminate as well as the predetermined grain size distributions so that the thermal expansion coefficient of the ceramic product is substantially equal to that of platinum and platinum alloys and in a range of from 9×10−6 K−1 to 15×10−6 K−1.

Abstract: A method for the manufacture of dense-sintered glass-ceramic shaped objects which have a coefficient of thermal expansion, .alpha., of -0.5.times.10.sup.-6 /K to 1.8.times.10.sup.-6 /K in the range between 20.degree. C. and 700.degree. C. whereby ceramizable glass powder and/or glass-ceramic powder from the system Li.sub.2 O-Al.sub.2 O.sub.3 -SiO.sub.2 is slip-cast by means of porous molds, dried, pretempered if necessary at temperatures up to 600.degree. C., vitrified and then sintered until the sintering temperature is reached up to relative densities of greater than 0.96 and ceramized, and whereby the glass powder and/or the glass ceramic-powder is prepared in a first grain size fraction of less than 63 .mu.m, in particular less than 45 .mu.m, and in a second grain size fraction of less than 7 .mu.m, in a ratio of the fractions to one another between 2:1 and 4:1, to form a stable, pourable slurry.